Pentabromobenzylester monoacrylate, hereinafter called PBB-MA for the sake of brevity, is the monomer from which poly(pentabromobenzylester acrylate) (PBB-PA) is prepared. PBB-PA is known in the art to possess flame retardant properties and is known to render otherwise flammable synthetic resins flame-resistant. The process for the preparation of PBB-PA according to the known art is disclosed, e.g., in DE 25 27 802, and presents several serious drawbacks. First of all, the reaction is carried out in solution in an organic solvent, which is expensive and requires relatively large reaction volumes, and further, the reaction times required are relatively long, being in the order of a number of hours. Futhermore, the normally employed solvent, methyl ethyl ketone, is a relatively hazardous material, and the process involves the handling of hazardous wastes.
Another drawback of conventional processes lies in the limitation of the reactor size, because of the danger of uncontrolled mass-polymerization. These processes further require heavy investments in equipment, to allow for elevated operation pressure and tight conditions. Moreover, reactor's walls fauling (encrustation), lump formation and agitator's blocking also represent serious problems.